Document display system for organizing and displaying documents as screen objects organized along strand paths

ABSTRACT

A system for displaying documents on a computer controlled display device is disclosed. The system displays documents either in a completely free-form, user controlled configuration or as strands, such that documents in a strand follow a strand path. The strand path is a two dimensional line through a three dimensional display space. The documents displayed on the strand are known as child documents, and each strand also has a parent document. Various constraints defining the strand are associated with the parent document, including a strand function defining the strand path, minimum and maximum separation constraints defining the distance between the child documents on the strand, and an origin constraint defining the positional relationship of the strand path to the screen object of the parent document.

FIELD OF THE INVENTION

The invention relates generally to office management, and morespecifically to the representation and manipulation of documents on adisplay device.

BACKGROUND

People have been using computers to work with their documents for years.In known systems, finding documents often means an expedition through amaze of directories and folders, and even simple jobs require learning amysterious language of commands and data objects.

In known two-dimensional user interfaces, folders or directories areused to organize files or documents into groups and hierarchies. Thetraditional way of dealing with grouping documents is to use containers,directories or folders. A directory or a folder is a container in whichyou put other objects.

A problem with the known two-dimensional user interfaces is thatdocuments in containers or directories are hidden from the user. Theuser is therefore unable to easily browse through the documents in thesystem. The user typically cannot see the documents inside a containerwithout opening up the container.

For these reasons and others, a new system of document representation isrequired, which allows users to easily manipulate documents in anenvironment like the real world of the desktop, where documents are nothidden inside containers. The new system should enable the user toorganize documents in a way that is intuitively appealing, and is notbased on artificial constructs imposed by the nature of computer storageof documents or two dimensional user interface displays.

SUMMARY

The disclosed system combines the computational and storage power of acomputer with an environment that is as natural as the space outside thecomputer. In the space outside the computer, it's a simple matter tofind a document within a pile on a desk, scan its contents, and locatethe needed information. The disclosed system provides a similar,visually rich environment for handling documents with a computer system.Documents may be typed, scanned, or faxes sent by remote users. Thesystem allows the user to organize and browse documents in anenvironment that resembles the real world of piles and papers.

In accordance with principles of the invention, there is provided asystem for displaying documents on a computer controlled display deviceis disclosed. The system displays documents either in a completelyfree-form, user controlled configuration or as strands, such thatdocuments in a strand follow a strand path. The strand path is a twodimensional line through a three dimensional display space. Thedocuments displayed on the strand are known as child documents, and eachstrand also has a parent document. Various constraints defining thestrand are associated with the parent document, including a strandfunction defining the strand path, minimum and maximum separationconstraints defining the distance between the child documents on thestrand, and an origin constraint defining the positional relationship ofthe strand path to the screen object of the parent document.

The system provides a powerful interface for manipulating documentsthrough a display device. The representation of documents on strandsenables the user to arrange documents on the display device in usefuland intuitive ways.

These and other features and advantages of the present invention willbecome apparent from a reading of the detailed description inconjunction with the attached drawings in which like reference numeralsrefer to like elements in the several views.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing of a strand;

FIG. 2 is a drawing of a strand that has been selected by a user;

FIG. 3 is a drawing of a pile and scroll tool with a strand;

FIG. 4 is a drawing of a tile strand of documents;

FIG. 5 is a drawing of a corkscrew strand of documents;

FIG. 6 is a drawing of an embodiment the system;

FIG. 7 is a drawing of a second embodiment of the system;

FIG. 8A is a drawing of a repository node having a repository interfaceand coupled with repository storage;

FIG. 8B is a drawing showing the logical processes within a repositoryinterface;

FIG. 8C is a drawing of a repository node having repository storage inthe form of a disc drive;

FIG. 9 is a drawing of a find tool with an output strand having a knot;

FIG. 10 is a block diagram of the architecture of a document displaysystem using strands;

FIG. 11 is a flow chart showing the steps of a method for schedulingusing a blocked queue and an execution queue;

FIG. 12a is a drawing of an example embodiment of an attribute shownhaving a name, a delimiter, and a value;

FIG. 12B is a drawing of a second embodiment of an attribute shownhaving a name, a value, and delimited by parentheses;

FIG. 13 is a diagram of showing a system having asynchronous remoterepository access;

FIG. 14 is a diagram showing the steps of a find tool method forretrieving documents from repositories;

FIG. 15 is a diagram of an apparatus for sharing a document between twousers;

FIG. 16 is a diagram of an apparatus for merging multiple documentsbased on their visual display attributes; and

FIG. 17 is a diagram of an apparatus for retrieving documents fromrepositories and having no busy cursor.

DETAILED DESCRIPTION Documents

A document is the primary object in the system. All data are containedin documents. A document contains some number of attributes, eachattribute having a name and a value. The set of attributes for any givendocument is arbitrary, and no particular attributes are required of alldocuments.

A screen object is the visual representation of a document. It may bevisible or hidden at any given time. Screen objects are generallyrectangular.

A Unique Identifier, or UID, is a string of alphanumerics that uniquelyidentifies a document. A UID is necessary and sufficient to refer to aspecific document.

Attribute Value Pairs

An attribute is a piece of data stored in a document. Each attribute hasan attribute name and an attribute value. An attribute name uniquelyidentifies an attribute value within a document.

The Script Interpreter

Script consists of a scripting language that can be executed to performsome action. It is stored in attribute values. Scripting language is alanguage used to specify commands to the system environment.

The script interpreters (architecturally there can be any number)interpret script which is stored in attributes of documents. Scripts canmodify attributes of documents, perform basic mathematical and searchoperations, call other scripts, and do other basic operations such asinsert or remove documents from strands. Most of the actions in thesystem are activated by calling scripts within documents.

Documents are the single abstraction structure in the script language.There is no persistent storage associated with the script environmentother than attributes of documents. Most of the actions in the system(other than simple dragging of documents) are activated by callingscripts within documents. A document consists of attribute/value pairs;by referencing an attribute in an expression, the value is returned.

The value of any attribute, ephemeral or not, may be executable script.Script thus allows the power user to extend the functionality of thesystem. For example, a user may define the value of an attribute bywriting his or her own script as the value of that attribute.

Whether an attribute is executable or not is typically established byconvention. For example, for a given implementation, an architecturallydefined set of messages may indicate that the attributes referenced bythe messages are executable. Or, a button on the mouse may bearchitecturally defined to invoke and execute the script contained in anattribute of the document in which the cursor is located when thatbutton is clicked by the user. In addition, or as an alternative, anidentifier process can be designed and used to determine whether thevalue of an attribute is script, and also what script interpreter isneeded to interpret it. The identifier process does not test whether thescript can be properly parsed, but upon determining that the value of anattribute is script, chooses which script interpreter to call tointerpret the script. For example, the identifier process can select aninterpreter for a dialect of the Lisp programming language by checkingthe first non-whitespace character to see if it is a left paren orsingle-quote. If the first non-whitespace character is a left paren of asingle-quote, the identifier process selects the interpreter for thedialect of the Lisp programming language to interpret the script.

A goal in designing a particular script language is that the scriptlanguage be easy to read. Users may not be computer scientists, but willnevertheless want to examine and modify scripts to a certain extent.Therefore the language must have few special characters, and generallyuse natural language words instead of symbols.

The script language should be uniformly structured, in that the onlystorage entity (object) in the language is a document consisting ofattribute/value pairs. Values may be atomic, such as strings, numbers,dates, or images, or they may be pointers (UID's) to other documents.Global objects may be stored as attributes in a universal "global"document which is visible to all scripts.

Attributes are generally not typed, but values are generally typed. Thetypes of values are used to determine what operations are permissible. Ascript is executed within a document by evaluating an attribute whosevalue is a script, and whose type is executable.

Inputs to the System

An example embodiment of the system includes an input device, forexample a mouse, to obtain information from the user regarding selectingand moving documents within the display. It will be clear to one skilledin the art of user interfaces that devices other than a mouse, such as alight pen, a voice controlled display, or a touch sensitive screen, arepotential alternatives to the mouse.

The locations of mouse events, for example the pressing and or releasingof a mouse button, are recorded as the UID of the document in which thecursor is located when the mouse event occurs. The x, y or z position ofthe cursor at the time the mouse event occurred is recorded. The resultsof user actions to select or deselect one or more documents aresimilarly recorded.

Scanning Documents

Any paper document can be entered into the system by scanning. Whenscanning a document into the system, a cover sheet should be used. Eachcover sheet is encoded with the identification of the owner of thedocument. Such identification would, for example, consist of the uniqueuser name defined within the system used to log-on or gain access tosystem.

In an example embodiment, when a document is scanned into the system,the scanned document is automatically placed in an IN BOX pile of theowner of the document. Each scanned document has an information stickeracross its top displaying the name of the owner and the date it wasscanned. The cover sheet is not included.

Scanned documents without cover sheets, or that have cover sheets thatdo not name valid users, cannot be delivered to the true owner of thedocument by the system. The system may be configured to deliver suchscanned documents to a designated user, who is responsible fordetermining the owner of the scanned documents.

The Visual Presentation: The Workspace

A workspace is a virtual three dimensional space in which a set ofdocuments are arranged. In this way a workspace contains a set ofdocuments. Within a workspace, there is a list of the documentscontained within the workspace, consisting of combinations of repositoryidentifiers (RIDs) and unique identifiers (UIDs). Also, for eachdocument within the workspace there exist ephemeral attributes, whichdescribe the current visual display of that document within theworkspace. Examples of ephemeral attributes include the X, Y, and Zpositions of the document within the workspace.

A workspace is stored in a workspace document and displayed in aworkspace window. A workspace document is a document that contains allof the state information of a workspace. A workspace document may becontained within other workspaces.

The display of a workspace on the display device is the "screen space"representation of the three dimensional workspace on the two dimensionaldisplay device. In an embodiment of the system, the screen space displayof a workspace is implemented through a window in the host computer'swindowing system, within which the two dimensional screen spacerendering of the three dimensional workspace is displayed.

The system uses a three dimensional workspace to provide a usefuldisplay of potentially thousands of documents. A workspace may displaythousands of documents. In a preferred embodiment of a workspace, theworkspace is wrapped at the edges, giving a fish-eye lens effect, sothat every screen object that is not invisible has at least some portionof its rectangle within the screen display no matter what its positionin the three dimensional workspace.

Workspaces may be shared, such that multiple users have the sameworkspace open. For example, user one and user two could simultaneouslyhave the same workspace open. In one embodiment, when user one drags adocument within the workspace, user two sees it moving as well. Theephemeral attributes defining the visual representation of the documentswithin the workspace can be mediated via repository connections fromuser one to user two to support this feature. For example, both user oneand user two could simultaneously read and write to a shared copy of theworkspace document within a mutually accessible repository.Alternatively, user one and user two could maintain separate copies ofthe workspace document in their respective client modules, establish adirect network connection between them, and exchange ephemeral attributeupdates via the direct network connection.

The Renderer Process

A renderer process is an element of the system that maintains thevirtual three dimensional workspace. The renderer process is performedby various specific renderers.

A document renderer is that portion of the system that draws inside therectangle of the screen object associated with each document in aworkspace. The system supports multiple renderers, and which renderer isused for a particular document is determined by an attribute of thatdocument.

A workspace viewer is a process in the system responsible for outliningthe screen objects of documents within the workspace and managing thedisplay of selection indication. The interior of each screen object isrendered by its associated renderer, and the workspace viewer completesthe view. The workspace viewer is also that part of the system which isresponsible for maintaining the view of a workspace. That is, theworkspace viewer contains the means for arranging documents inthree-space.

Ephemeral Attributes

Ephemeral attributes are attributes associated with a document in thecontext of a workspace. Ephemeral attributes are stored within aworkspace document of the workspace containing the screen object of thespecific document which the ephemeral attributes are associated with.Ephemeral attributes define the display characteristics of theassociated document, such as position and size. Ephemeral attributesreflect the actions of the user in manipulating the screen object of adocument within a workspace, typically through using an interface devicesuch as a mouse.

Ephemeral attributes are stored in workspace documents, which in turnare stored in repositories. All the state information of the last imageof a workspace, including ephemeral attributes associated with eachdocument in the display, is stored in the permanent attributes of aworkspace document when that document is stored into a repository. Thusa document may have different ephemeral attributes and values when thatdocument is associated with different workspaces.

An ephemeral document is a document that has existence only in aworkspace. It has no permanent attributes, only ephemeral ones. In analternative embodiment, ephemeral documents may be stored in a virtual"workspace repository", accessible only from its workspace, and may havepermanent attributes in this context. In such an alternative embodiment,the state of the workspace repository is stored as an attribute of theworkspace document.

An intrinsic ephemeral attribute, or intrinsic attribute, is a specialephemeral attribute that every document must have, which directlyeffects the display of the screen object. Examples include x position(xpos), y position (ypos) and z position (zpos). Many intrinsicattributes are available for direct manipulation through the userinterface device.

The Perspective Function

A perspective function maps objects on the screen by taking the threedimensional workspace coordinates, or "world space coordinates",maintained by the workspace viewer, and mapping them intotwo-dimensional screen space positions.

For example, every document has a position in world space defined alongthe x, y, and z axis, and every document has a width and a height. Whenan image of the document is drawn on the display device, the perspectivefunction takes those world space coordinates and size variables as inputparameters, and determines the actual size and location on the displaydevice, in "screen space coordinates", where the document is actuallygoing to be drawn. The perspective function is instantiated by theworkspace viewer process.

Dragging Along the X, Y or Z Axis

To move a document around a workspace, there are three basic actions:dragging around, pushing back/pulling forward, and clipping. Dragging adocument is the act of moving the corresponding screen object for thatdocument with respect to one or more of the x, y, and z axis of theworkspace by manipulation of the user interface device.

To move a document within the workspace, the user uses the userinterface device to place the mouse cursor near the center of screenobject of the document. The user next presses and holds the mouse buttonwhile moving the mouse. As a result, the screen object disappears and isreplaced by an outline of its shape (called a drag box). As the mouse ismoved, the drag box follows. This is known as dragging. When the mousebutton is released, the screen object reappears in its new position.

Documents are pushed back and pulled forward via a modified drag action,e.g. using a separate mouse button, or by first moving the mouse cursorclose to a corner of the screen object of the document, and thenpressing and holding a mouse button. As an alternative a track balldevice may be used to manipulate the position of the mouse cursor. Asthe mouse cursor is moved toward the bottom of the screen, the screenobject is dragged forward (towards the user) within the workspace. Asthe mouse cursor is moved toward the upper left corner of the screeninstead of forward, the screen object is pushed back within theworkspace. Note that as the screen object on the display device is beingmoved, the virtual location of the corresponding document maintained inthe world space of the workspace viewer is being changed accordingly.Thus one can either say that the screen object is being moved, or thatthe document is being moved, and have the same meaning.

As a document is pulled forward, the document is moved towards the useralong the z axis of the three dimensional workspace. The perspectiveprocess translates this movement of the object towards the user into ascreen representation of the screen object for the document. As aresult, the screen object for the document grows in size in its twodimensional screen space representation. Conversely, when a document ispushed back, the screen object for the document is made smaller.

A document can only be moved forward a certain distance. When it is asbig as it will get, it is plastered against the workspace window andcannot be moved any closer.

The world space size of a screen object is the size of the screen objectin the three dimensional space of the workspace. This is the object'sreal size opposed to the screen space size at which it appears on thescreen display surface. Documents and elements of documents (e.g.buttons, text fields, etc.) all have world space sizes. Althoughdragging along the Z axis can make the world space size of documentsvery small, they will never be rendered at a size that is invisible tothe user.

In the case of "corner dragging" in the Z dimension, any of the fourcorners of a document may be used to push or pull it. However, thedocument will move along somewhat different paths depending on whichcorner is used.

Repositories

A repository is a data store that contains documents. A workspace isgenerally used for short term storage of documents. For long-termstorage, documents are kept in repositories. When a system tool bringsdocuments into a workspace, it gets them from repositories. A RepositoryIdentifier, or RID, is a string of alphanumerics that uniquelyidentifies a repository. RIDs are unique on the network. An RID isnecessary and sufficient to refer to a repository. In an alternativeembodiment RIDs are universally unique, and therefore permanently stablein a global environment where mobile computing is increasingsignificant. For purposes of example, such universally unique RIDs maybe assigned through a central RID allocation system, similar to how 48bit Ethernet physical layer addresses are centrally assigned to specificnetwork controllers, to guarantee that there are no duplicates.

The computer network that the system is connected to may have onerepository available or it may have many. Some repositories are genericplaces to put documents, while others may be specialized. For example, amachine that sends and receives documents as faxes over telephone linescan be a repository. The user may choose to maintain a privaterepository on the local computer. Most repositories are on remotemachines and the system gets documents from them over the network. Arepository may exist on the local file system. An embodiment of thesystem may run on a system with no disks. In that case, all repositoriesexist within remote network nodes.

The user may retrieve documents from many different repositories at thesame time. Similarly, multiple users can connect to the same repositoryat once. A user of a document may put a document into a sharedrepository marked to the attention of other specified users. Each usermay configure a special FIND tool (which serves as their IN BOX) thatconstantly watches the repositories for documents marked for theirattention and brings them into their workspace. In this way, documentsmay be shared between users.

Repositories are visually represented in a workspace by a documentcalled a repository portal. The user accesses a repository through therepository portal for that repository. A repository may be passwordprotected, such that the user may have to enter a password into theportal document before using the repository.

Repositories may have special characteristics (unusual connectionrequirements, limited hours of availability, etc.) These are representedto the user on the portal document. Repository portals also have avisual indication of whether their repositories are currently availablefor use.

A repository server is a server that serves documents from a repositoryto a client and provides a search engine, and repository interface toprocess search requests described by attribute value pairs from theclient system, and to search the repository using the search protocolspecific to that repository.

Strands

Strands are a system for positioning screen objects in athree-dimensional workspace. Strands allow grouping of documents, sothat they can be manipulated as groups. Strands are a method of applyingconstraints to the organization of screen objects in three dimensions.

A strand is associated with a first document (the "strand parent"), andconstrains the location of a set of documents not containing the strandparent. A strand is a process that maps a (possibly discontinuous) lineinto 3 space. Each strand child has a position on the strand relative tothe strand origin. A strand also has minimum and maximum constraints forthe spacing of its children.

Strands are not containers, but rather are a mechanism for arrangingscreen objects without hiding them. A strand constrains the position ofscreen objects attached to the strand into a certain shape. The certainshape is indicated by a strand function. When the strand function isevaluated, its output defines a strand path. A pile is an example of astrand where all the documents attached to a strand are constrained tobe next to each other in the shape of a pile.

The strand path is mathematically defined as a one-dimensional paththrough three dimensions, along which are displayed the screen objectsof the child documents of the strand. Objects attached to a strand pathappear to be indirectly connected, as do pearls on a strand of string.The strand function can be arbitrarily set so that it is oriented in anydirection or is any complex line. It can be a complicated function likea bunch of line segments joined together, or it could be U-shaped orzigzag-shaped.

A pile of documents is a strand having a strand path defined by afunction causing the strand to be oriented substantially parallel to theZ access of the display, that is, going straight back from the surfaceof the display device that is closest to the user. A "tile" of documentsis a set of documents placed next to each other so that the completecontents of their current screen objects are showing. A tile is definedas a strand having a strand path substantially parallel to the glass ofthe screen. The strand mechanism itself is completely general. The usermay define a corkscrew strand path to have documents spiraling back intoinfinity if so desired.

An example of a system tool having a strand is as follows. The FINDoperation may be a tool having a pile for its output. The FIND commandlocates documents, and puts them into a pile below itself. The outputpile is attached to the FIND tool. When the FIND tool is moved, the pilefollows. The FIND tool will "let go" of a document if the document isclicked and dragged away from the pile.

A strand parent is a document to which a strand is attached. The strandpath for that strand is defined relative to an origin point defined withrespect to the strand parent. For example, the strand path could berelative to an origin in the upper left corner of the screen object forthe strand parent. Minimum and maximum separation constraints,associated with the strand parent, define the spacing between any twochild documents on the strand to be greater than the separation minimumand less than the separation maximum. The minimum and maximum separationconstraints may for example be stored in the strand parent.

FIG. 1 shows a display device 10, including an example of a strand 15.The strand 15 is shown having child document screen objects 19a, 19b . .. 19e, and parent document screen object 17. The strand path is shown byline 20, and the mouse cursor is shown by element 21. The separation ofthe child document screen objects 19 is shown at 24.

During operation of the system, with reference to the elements in FIG.1, the strand path 20 is calculated by evaluating a strand functionassociated with strand parent represented by screen object 17. The exactorientation of the strand path 20 is determined with reference to anorigin constraint associated with the strand parent screen object 17,for example, the upper left hand corner of the strand parent screenobject 17 at point 26. The outputs of this evaluation are threedimensional coordinates that define the strand path 20 in the virtualrepresentation maintained by the workspace viewer.

The child documents of the strand (corresponding to screen objects 19)are determined from a list of unique identifiers of the child documentsassociated with a strand parent document corresponding to screen object17. The separation constraints associated with the strand parentdocument, indicating the minimum and maximum separation of childdocuments displayed along the strand path 20, are also evaluated. Theoutput of these evaluations provides three dimensional coordinatesdefining the appearance and location of the child document screenobjects 19 along the strand path 20.

The three dimensional coordinates are passed to a perspective processfor translation into two dimensional screen space coordinates. The twodimensional screen space coordinates are used to display screen objects19, representing child documents along the strand path 20, on thedisplay device 10. The strand path 20 itself is not typically, but maybe displayed on the display device. The separation 24 between the childdocuments cannot exceed the maximum separation constraint, and is notless than the minimum separation constraint associated with the strandparent document corresponding to screen object 17.

Strand parents may further include a knot constraint, defining points inthe strand that divide the strand into sub-strands. Knot constraints maybe arbitrarily defined, and are generally invisible to the user. Forexample, knot constraints may be used to subdivide the strand into twosub-parts so that the user has a pile of mail that has been read, and apile of new mail, both within a single strand. Knots are used to keepthose sub-strands (or sub-piles) separated.

Two applications for strands are presentation of documents in piles ortiles, and grouping documents. A strand is an object on the displaydevice, and the user can pick up the strand by using the mouse to selectthe parent document of the strand. All of the strand's children aremoved when the strand itself is moved. The system may be configured suchthat when the user selects a child document on the strand and moves it,the document is removed from the strand. In the alternative, the systemcan be configured such that moving any child document on the strandcauses the entire strand and all other documents on the strand to movewithout removing the child document from the strand.

In the example shown in FIG. 1, the parent document corresponding toscreen object 17 is a FIND tool. For example, the FIND tool may be usedto locate documents containing a particular string of characters. Whenthe FIND tool is used, the documents found to contain the string aredisplayed along the strand 15, in this case, a pile. The FIND tool isthe parent of that strand. When the screen object for the FIND tool ismoved on the display device, the pile is dragged with it.

In FIG. 2, the elements shown in FIG. 1 are shown after the user hasselected the screen object 17 of the strand parent for the strand 15.While the strand parent screen object 17 is selected, the user has alsoselected the entire strand 15, including child document screen objects19. The strand parent screen object 17, and the child document screenobjects 19 are shown as outlines while the strand 15 is selected.Further, while the strand 15 is selected, the user may use the mouse tomove the cursor 21 around the display device 10, thereby moving theentire strand 15.

After the strand 15 is moved to its desired position, the user maydeselect the strand 15, causing the screen objects 17 and 19 for thestrand parent and strand children to be filled in again.

In another example embodiment of a system tool using a strand, a pileand scroll tool is used to browse through a collection of documents. Ituses a U-shaped strand that tiles a few of the documents and piles otherof the collected of documents. The use of the U-shaped strand makes theuse of the tool more intuitive for the user, since both the currentlytiled documents are displayed simultaneously with the piled documents.

The pile and scroll tool 60 is shown in FIG. 3. Pile and scroll has aU-shaped strand function 62, including a first pile 64 and a second pile66. In the configuration shown, first pile 64 in FIG. 3 is on top of atiled section 68, and second pile 66 is on the bottom of the tiledsection 68. The system allows other configurations and orientations ofthe strand. Documents 68a, 68b, 68c, and 68d, are shown in the tiledsection between piles 64 and 66, and are tiled parallel to the screen.

The tile and scroll tool 60 in FIG. 3 has a control button 70, with uparrow 72 and down arrow 74. When the user brings the mouse cursor overup arrow 72 within the control button 70, and then clicks once on themouse button, the tile and scroll tool 60 moves document 68a backwardsinto first pile 64, moves the documents 68b, 68c, and 68d upwards withinthe tiled documents 68, and brings forward a document from the secondpile 66 to be displayed within the tiled section 68. If the user holdsthe mouse button down and does not release it while the mouse cursor isover the up arrow 72, multiple documents are continuously tiled intoview from the second pile 66 until the mouse button is released.

Similarly, when the user moves the mouse cursor over the down arrow 74,and clicks once on the mouse button, a document is tiled into view fromthe first pile 64, and holding down the mouse button tiles multipledocuments from first pile 64 until the mouse button is released. In thisway, the user can browse through multiple collected documents using thepile and scroll tool 60.

In tiling, the documents look like they're beside each other, likepieces of paper on a table. They appear at the same distance from theuser. Therefore, documents that are tiled are at the same Z position inthe workspace, relative to the front of the display device.

In an example tile 80 shown in FIG. 4, the strand function 82 runsparallel to the screen, so that the documents 80a through 80g arethreaded along the strand parallel to the screen. In a tile, the worldspace coordinates of the strand as maintained in three dimensions by theworkspace viewer is parallel to the screen. In a pile, as shown above,the strand is not parallel, but perhaps perpendicular to the screen.

Thus it is seen that the strand function is an arbitrarily definablegeometric function. An implementation may offer the user multiplepre-calculated strand functions, or an interface through which the usercan define her own strand functions. As a further example of theflexibility of display provided by strands, FIG. 5 shows a corkscrewpile 90, having a strand function 92 defining a corkscrew shape.

FIG. 6 shows an example embodiment of the document display system. Amother board 605 is shown having daughter boards 610, individuallynumbered 610a, 610b, 610c and 610d. The daughter boards 610 are coupledwith the mother board 605 through parallel bus 615. Daughter board 610ais coupled with a display device 10 through serial interconnect 635,daughter board 610b is coupled with user input device 620, and daughterboard 610c is coupled with repositories 625 via network 640.

During operation of the elements in FIG. 6, the user manipulates theuser input device 620, thereby sending user input commands to thedaughter board 610a. The logic within the daughter boards 610 thenresponds to the user commands by changing the view on the display device10, and requesting and retrieving documents from the repositories 625.

FIG. 7 shows elements in an example embodiment of the system. A displaydevice 10 is shown displaying the example from FIG. 1. The displaydevice 10 is coupled with a display controller 610 through serialinterconnect 635.

The display controller 610 includes a memory 25, the memory 25 havingparent document 27 (shown as screen object 17 in FIGS. 1 and 2), andchild documents 29a, 29b, . . . 29e (shown as screen objects 19 in FIGS.1 and 2). Parent document 27 includes minimum and maximum separationconstraints 37 and 39 respectively, child document list 41, containingthe unique identifiers for the child documents 29, strand originconstraint 43 and strand function constraint 45. The child documents 29each contain parent pointer 47, containing the unique identifier of theparent document 27, and flags field 49, containing flags indicatingwhether the child may be removed from the strand when selected, andwhether the child is to be displayed or concealed when the strand isdisplayed.

Also shown in FIG. 7 are processor 31, coupled with memory 25, as wellas workspace viewer 35, and script engine 36. Script engine 36 andworkspace viewer 35 are shown as processes running on processor 31, butit will be evident to one of skill in the art of computer science thatthese processes could alternatively be implemented in hardware, such asan application specific integrated circuit, or in firmware or microcode.

Also contained within each document is a document renderer attribute forthat document. For example, parent document 27 contains documentrenderer attribute 57, and child documents 29a through 29e containdocument renderer attributes 59a through 59e. The value of the documentrenderer attribute for each document indicates the document renderer forthat document. In the example of FIG. 7, renderer attribute 57 indicatesa document renderer 700, renderer attribute 59a indicates a renderer701, and renderer attribute 59b indicates a renderer 703. Further,renderer attribute 59c indicates a renderer 704, renderer attribute 59dindicates a renderer 702, and renderer attribute 59e indicates arenderer 705. Thus in the example of FIG. 7 each document indicates apotentially different document renderer.

Each document may optionally contain a layout attribute, having a valueequal to a script used to control the document renderer for thatdocument. The script within the value of each layout attribute iscapable of being interpreted by a script engine within the system, forexample the script engine 36. In the example of FIG. 7, parent document27 contains a layout attribute 710, for controlling the renderer 700,child document 29a contains a layout attribute 711 for controlling therenderer 701, child document 29b contains a layout attribute 712 forcontrolling the renderer 703, child document 29c contains a layoutattribute 713 for controlling the renderer 704, child document 29dcontains a layout attribute 714 for controlling the renderer 702, andchild document 29e contains a layout attribute 715 for controlling therenderer 705.

Now with reference to the elements of FIG. 7, operation of the system isdescribed. The workspace viewer 35 uses constraints from the strandparent document 27 to create three dimensional world spacerepresentation of the strand 15. The workspace viewer 35 maintains thecurrent view to be displayed on the display device 10, includingoutlines of those documents currently displayed, and informationdefining which documents are currently selected. The document rendererattributes 57 and 59a through 59e indicate the document renderers 700through 705 to be used to fill in the screen objects of those documentscurrently displayed on the display device 10. The workspace viewer 35contains a perspective function to translate between three dimensionalworkspace coordinates and two dimensional screen space coordinates.

In a preferred implementation, document renderers 700 through 705 areimplemented in an efficient programming language such as C, andcontrolled during execution by a script language contained in the valuesof layout attributes 710 through 715. The script in the values of layoutattributes 710 through 715 is interpreted by the script engine 36. Theprimary task of the script language in this context is to set the valuesof attributes within documents. The script language therefore requiresfew verbs, as the values of a pre-defined set of attributes, known asintrinsic attributes, are used to control associated functions in therenderers 700 through 705.

The strand function 45 within strand parent 27 is a mathematicalequation defining the strand path. The workspace viewer 35 processes thestrand function 45 to obtain three space coordinates for the strand path20 of the strand 15. The workspace viewer 35 inputs the strand originconstraint 43 to adjust the actual orientation of the strand path 20relative to the upper left hand corner 20 of the screen object 17 of thestrand parent 27.

The workspace viewer 35 inputs the child document list 41 and theminimum and maximum spacing constraints 37 and 39 to create world spacethree dimensional coordinates for the child documents along the strandpath 20. The workspace viewer 35 passes the world space coordinates ofthe child documents 29 through a perspective process, which converts thethree dimensional coordinates into two dimensional screen spacecoordinates. The workspace viewer 35 then sends the resulting screenspace display through serial interconnect 635 to display device 10,causing the outlines of the screen objects of strand 15 to be displayed.

The layout attributes 710 through 715 are interpreted by the scriptengine 36. The system allows use of multiple script engines, and adocument may either contain indication of which specific script engineto use to interpret the layout attribute for that document and thuscontrol the document renderer for that document.

FIGS. 8a through 8c show an embodiment of a repository node 800. In FIG.8A, the repository node 800 consists of a repository interface 805coupled with a repository storage 810. During operation, the repositoryinterface 805 receives repository requests from a client on a network835. The repository interface 805 interprets the repository requests,and returns data from the repository storage 810.

FIG. 8B shows the logical processes within the repository interface 805.The repository interface 805 is shown to include an attributeinterpreter process 815, coupled to a database standard query language(SQL) library 820. During operation, the attribute interpreter process815 receives repository requests from the network 835, and translatesthe repository requests into database SQL commands, which are passed tothe database SQL library 820. The database SQL library 820 returns theresults of the commands issued by the attribute interpreter process 815,and the attribute interpreter process 815 then responds to therepository requests over the network 835. In this way, the attributeinterpreter process 815 translates between the protocol of requestsbased on attribute having names and values, and the database SQL.Repository requests therefore may be based on attributes having namesand values, independent of the type of search language used within theindividual repository.

FIG. 8c shows a repository node 870, having repository storage in theform of a disc drive 810, and also having a repository interface 805.The repository interface 805 is coupled with the disc drive 810, as wellas the network 835. The repository interface 805 includes the attributeinterpreter process 815, as well as the database SQL library 820.

During operation of the elements in FIG. 8c, the repository interface805 receives repository requests over the network 835. The repositoryrequests refer to documents in terms of attributes having names andvalues. The attribute interpreter process 815 translates the repositoryrequests into calls to functions in the database SQL library 820. Thedatabase SQL library 820 functions return information stored on discswithin the disc drive 810. The attribute interpreter process 815 thenresponds to the repository requests with the information returned by thedatabase SQL library 820, formatting the responses into attribute valuepairs.

A strand may be defined having one or more knots that divide the strandinto substrands. FIG. 9 shows a find tool 100 having an output strand101, the output strand 101 having parent find tool document 103, andchild documents 100a, 100b, 100c, 100d, and 100e. The output strand 101further is shown having a knot 104, the knot 104 dividing the outputstrand 101 into a first substrand 106 and a second substrand 108. Thefirst substrand 106 contains child documents 100a, 100b, and 100c, andsecond substrand 108 contains child documents 100d, and 100e.

During the operation of the elements shown in FIG. 9, the user activatesthe find tool 100 to search for needed documents, for example, thosemail messages received from a given sender. The user also specifies agrouping for the find tool to use, for example all such mail messagespreviously read versus those not yet read. The user specifies thatpreviously read documents be displayed in the background of the displayrelative to documents not yet read. The find tool 100 then locates thosemail messages received from the specified sender.

The find tool 100 puts the unread mail messages received from thespecified sender in the foreground of the output strand 101, followed byknot 104. Therefore, in the example of FIG. 9, the child documents 100a,100b, and 100c are mail messages received from the specified sender,that are not yet read. The find tool 100 puts those mail messagesreceived from the specified sender that have been read after the knot104, in substrand 108. Thus, child documents 100d and 100e are mailmessages from the specified sender that have previously been read.

As an alternative, the user requests that all mail messages receivedafter a specified date be grouped in the foreground, and all others inthe background. The knot 104 divides the two requested groups, and childdocuments 100a, 100b and 100c, in substrand 106, are those mail messagesreceived after the specified date, and child documents 100d and 100e, insubstrand 108, are those received prior to the specified date.

Sliding

Sliding is the direct manipulation mechanism for changing a strandchild's strand position. Other children of the strand may be rearrangedto satisfy the constraints of the strand.

A document may be moved along a strand through sliding, just likesliding a bead along a string. When the user slides a document on astrand, other documents on the strand move as well, either pullingbehind or pushing ahead of the sliding document. For example, if thestrand max constraint is set, other documents follow along the slidingdocument such that the max constraint isn't violated.

Sliding may be either a user driven event, or script driven event. Auser may slide a document by selecting the document with the cursor orother user interface device, and then directly changing the position ofthe document on the strand. Sliding may also be done when script isexecuted, for example as a result of execution of an attribute havingscript as a value.

The minimum and maximum separation constraints are evaluated such that aline in between the two documents in three space, in between the closesttwo points of the documents in three space, is guaranteed to be ofgreater length than the strand min and less than the strand max.

A document can be removed from the strand or inserted onto the strand. Auser may insert a document into a strand by dragging the screen objectfor that document into contact with the stand as displayed on thedisplay device. When the user performs this action, the document isinserted into the strand with which the screen object came into contact,and the document becomes a child document of that strand. Similarly auser may remove a document from a strand, by dragging the document awayfrom the strand, when the system is configured such that the stranditself is not moved by such an action. When the user drags the screenobject for a document away from the strand, the document is removed fromthe list of child documents contained within the parent document of thatstrand. Both of those operations cause the constraints of the entirestrand to be recomputed, resulting in other documents being repositionedon the strand if the constraints are no longer satisfied. When adocument is moved, the spacing constraints are re-evaluated. If thespacing constraints are no longer satisfied, the changes are propagatedto all of the documents to make sure that the documents are positionedin a way that causes the constraints to be satisfied. In animplementation of strands using knots, there may result a situationwhere it is impossible for all of the constraints to be satisfied. Thatis, there might be two knots and so many documents between them that theminimum distance constraint could not be satisfied. Under thosecircumstances the strand would spread the discrepancy out equally amongall the documents on the effected strand or substrand.

Components in an Example Embodiment of the System

FIG. 10 is a block diagram of the architecture of a document displaysystem. A user 120 interfaces with an input device 164, for example amouse and/or a keyboard, to detect user actions 122. A message handler124 is shown responsive to user actions 122. Message handler 124 isfurther coupled with a workspace viewer 128, such that message handler124 sends and receives dispatch messages 126 to and from workspaceviewer 128. The workspace viewer 128 is also coupled with a workspacecache 132, such that the message handler 124 can receive data changeevents from the workspace cache 132. The workspace viewer 124 is coupledwith a script engine 146, such that script engine 146 performs scriptevaluation 150 for the message handler 124.

The workspace cache 132 is coupled with repositories 142, and sendsrepository requests 140 and receives repository replies 141. Theworkspace cache 132 is further coupled with the workspace viewer 128,and the workspace viewer 128 is capable of reading and writing intrinsicattributes 130 in the workspace cache 132. The workspace cache 132 isalso coupled with a document renderer 136, and the document renderer 136performs attribute edits 134 on attributes within the workspace cache132. The workspace viewer 128 and the document renderer 136 are coupledwith a display device 160, by means of screen update operations 162.Also, the workspace cache 132 is coupled with a watchdog timer process138, and the script engine 146. The script engine 146 is capable ofperforming attribute edits 148 on attributes stored within the workspacecache 132. Those components within the dotted line 175 are core elementsof the system.

The interaction of the elements in FIG. 10 is now described. The messagehandler 124 coordinates the computation necessary to execute scripts inthe script engine 146, read and write data into the repositories 142,and keep the workspace on the screen consistent with data and useractions 122. The message handler 124 translates user actions 122 intomessages that are dispatched 126 to the workspace viewer 128.

The workspace viewer 128 manipulates screen objects in three dimensionsand allows direct manipulation by the user 120. The workspace viewer 128manipulates attributes stored in the workspace cache 132, that are fromdocuments stored in the repositories 142. The workspace viewer 128displays data (attributes) that are stored in a workspace document aswell as attributes of other documents referenced by the workspace viewer128. A workspace document contains references to other documents andwhen opened displays screen objects that display data (attributes)contained within the referenced documents. Approximately there is onescreen object per document reference.

Intrinsic attributes 130 are those attributes that each document has inworkspace cache 123 while it is being referenced by a workspacedocument. An example of an intrinsic attribute is the "X" position of adocument's screen object within the workspace window. Intrinsicattributes are sufficient to outline the screen object for a document.

The system maintains an asynchronous connection with any repositories142 that it needs to access, and makes requests to the repository forany information needed to complete the current display. Repositoryrequests are handled by an asynchronous remote procedure call mechanism.

The workspace viewer 128 operates on data contained in the workspacecache 132, from a workspace document. The workspace viewer 128 mapsattributes for each document referenced by the workspace document intothe outline of a screen object that is associated with that document.

For example, in an implementation of workspace viewer 128, the positionof a document on the screen is affected by changing the intrinsicattributes corresponding to the x position, y position, and z positionof the document in the context of the current arrangement of theworkspace document. Similarly, a direct manipulation by the user 120 ofthe screen position of a document changes the intrinsic attributes ofthat document.

The inside of the screen object for each document is rendered by adocument renderer 136. The workspace viewer 128 maintains the locationsof the screen objects within the workspace, draws the outline of thescreen objects, and then negotiates with the document renderer 136 tofill in each document. The document renderer 136 draws appropriate datainside the documents based on attributes of the documents. Each documentmay indicate its own document renderer 136, based on the value of adocument renderer attribute within the document. Both the workspaceviewer 128 and the document renderer 136 interpret user-manipulationmessages that are directed at screen objects in the current arrangementof the workspace document being displayed.

The script engine 146 executes script written in a system compatiblescripting language. Script is executed in the context of the workspacein which it was initiated, and is able to read, write, and search allattributes of documents in the workspace as well as add and deletedocument references from the workspace, and perform repository specificactions.

A further example of the operation of the example system in FIG. 10 isnow described. The user 120 initiates a user action 122, which isdetected by the message handler 124. The message handler 124 thenexecutes script using the script engine 146, and dispatches a message126 to the workspace viewer 128, thus translating the original useraction 122 into a command, or instruction for the workspace viewer 128.

The workspace viewer 128 receives the message 126 from the messagehandler 124, and reads those intrinsic attributes 130 effected by theuser action 122, from the workspace cache 132, and recalculates thoseattributes in the context of the three dimensional workspace. Theworkspace viewer 128 then writes the recalculated intrinsic attributes130 to the workspace cache 132.

The document renderer 136 is signaled to update the screen display foreach document by either a periodic watchdog process 138, or by a signalfrom the workspace cache 132 indicating that attributes within theworkspace cache 132 have been modified.

FIG. 11 is a flow diagram of steps performed by the message handler 124to handle events requiring script execution. In step 1100, the messagehandler receives a request indicating an event has occurred requiringscript execution. Next, step 1105, the message handler 124 determineswhether the script to be executed requires data from a repository. Ifthe script does require data from a repository, the message handler 124sends a message in step 1110 to the repository requesting the data, andputs the script to be executed onto a blocked queue in step 1115. If thescript to be executed can be executed without data being retrieved froma repository, the message handler 124 causes the script to be placedinto an execution queue in step 1120, to be interpreted by the scriptinterpreter and executed. When a response is received in step 1125 fromthe repository having data needed to execute script placed on theblocked queue in step 1115, the next step is step 1130. In step 1130,the script previously moved to the blocked queue in step 1115 is movedto the execution queue.

The Attribute Format

FIG. 12 is a diagram of an embodiment of the format of an attribute. InFIG. 12a, a first embodiment of an attribute 207 is shown having a name202, a delimiter 203, and a value 204. In FIG. 12b, a second embodimentof an attribute 206 is shown having a name 202, and a value 204delimited by parenthesis 205. The name 202 and the value 204 are groupedtogether in a list, delimited by outer parenthesis 206. In listprocessing languages, core operations are available to extract the firstelement of the list, in this case accessing the name 202 part of theattribute, and also to extract or evaluate the remainder of the listother than the first element, in this case the value 204 of theattribute. The value 204 of the attribute may consist of scriptlanguage, and when evaluated or referenced may be interpreted by thescript engine.

Scheduling Repository Requests

FIG. 13 is a diagram of an embodiment of the system having remoterepository access. The core elements 175 of the system (as shown in FIG.10), are shown coupled to windowing system interface module 200. Theinterface module 200 is coupled with the display device 160, and alsodetects user events 123 from a user 120. User events 123 are translatedinto user actions 122 as understood by the core elements 175. Theinterface module 200 receives screen update operations 162, andtranslates the screen update operations into drawing operations 163specific to the individual windowing system for the implementation. Theinterface module 200 is responsible for drawing on the display surfaceof the display device 160 and providing all user interaction events tothe core elements 175.

A client module 210 is shown coupled with a LAN 211, the LAN 211 in turncoupled with repositories 142. The client module 210 includes a networktransport layer module 214, and a queue of responses 212. The coreelements 175 are coupled with the client module 210, receivingrepository replies 141, and issuing repository requests 140.

During operation of the elements in FIG. 13, the client module 210 dealswith the interactions with the repositories 142. The client module 210supports making connections and asynchronous requests for data from therepositories 142. Responses are placed in the queue of responses 212.When the core elements 175 issue a repository requests 140, the clientmodule 200 calls the network transport layer module 214 to send arequest message over the LAN 211 to the repositories 142. When aresponse is received from the repositories 142 over the LAN 211 by thenetwork transport layer module 214, the client module 210 puts theresponse into the queue of responses 212. The core elements 175eventually dequeue the response from the queue of responses 212. In thisway, multiple repository requests 140 may be simultaneously outstanding,responses from the repositories 142 may be received asynchronously, andthe responses may be dequeued from the queue of responses 212 as isconvenient for scheduling by the core elements 175.

A Method for Retrieving and Displaying Document Information FromRepositories

FIG. 14 is a flow chart showing the steps of a method for retrievingattributes from repositories. In step 300 a FIND tool is activated toassemble files matching a given set of parameters into a strand. Forexample of a given set of parameters, the user could request the FINDtool to retrieve all files with a given extension, or of a common filetype. The find tool starts a first process 301, having steps 305, 310,315, 320, and 325. In step 305, the find tool sends repository requeststo a client module, requesting the client module to obtain files fromall repositories matching the given set of parameters. In step 310, theclient module sends requests over a LAN to the repositories, for filesmatching the given set of parameters.

As each repository receives the requests sent by the client module, therepository processes the request and issues a response for any filesmatching the given set of parameters. In step 315, the client modulereceives a response from one of the repositories, and enters theresponse into the queue for responses within the client module.Responses from the repositories may be received in any order.

Decision block 320 determines whether all the needed responses have beenreceived. This may be implemented either through a timer mechanism, orby requiring all repositories to respond whether or not they containfiles that match the given set of parameters. When all the responses arereceived from the repositories, decision block 320 terminates the firstprocess 301 in end state 325.

Second process 302 executes independently from, and in parallel withfirst process 301. After the FIND tool is activated in step 300, in step330 the workspace viewer adds the FIND tool strand to the workspace.Until responses are received from the repositories, the FIND tool strandwill contain no documents. While the FIND tool itself is the parentdocument of the strand, and the strand is visually anchored to the FINDtool, the parent document is not on the strand. As the responses arereceived from the repositories, those documents matching the given setof parameters are added as child documents to the strand.

In step 335, the queue for responses is checked for responses from therepositories. When a response is received indicating a document from oneof the repositories that matches the given set of parameters, a childdocument is added to the FIND tool strand in step 340. In step 345, itis determined whether the document renderer attribute for the childdocument has been received from the repository. If not, then in step 350a grey block is displayed on the FIND tool strand for the childdocument. When it is determined that the document renderer attribute hasbeen received from the repository, the child document is filled in atstep 355, by the renderer indicated by the renderer attribute.

Thus, as the FIND tool retrieves documents asynchronously from remoterepositories over a LAN, each retrieved document is added to the FINDtool strand in the order the response was received. Until sufficientinformation is received to fill in the display of the document, thedocument is displayed as a grey block. Therefore, the requests to therepositories do not lock up the workspace viewer, which may update theworkspace independently of the FIND tool operation, or may update theworkspace in part as the results of the FIND tool are asynchronouslyreceived over the LAN.

Clipping

To clip a document is to restrict the viewable area of the screen objectassociated with a document in a view. This may be done by dragging anyedge of a screen object toward its center. Clipping makes documents looksmaller without moving them back in the Z dimension. A clip stopconstrains the clipping edge of a document such that it can only beclipped to a specified set of positions.

Documents with clip marks contain hidden information beyond the edge ofthe document. The hidden information may be revealed by clicking on theclip mark, dragging the clip mark as far down as it will go, andreleasing the mouse button. This unclips the hidden information.

Annotating Documents: Information Stickers

Whenever a new document is scanned, faxed or sent through electronicmail, and then subsequently fetched to a workspace, the system willannotate that document to indicate that it has not been read. The systemmay staple an information sticker to the new document, thereby creatinga fixed visual relationship between the information sticker and the newdocument. After the information sticker is stapled to the document, theinformation sticker will be displayed in the position at which it wasstapled relative to the new document whenever the new document isdisplayed. The fields of the information sticker and their contentsdepend on where the document came from. The user can add or deletefields within the information sticker and edit them as needed. The userwill typically add information to help find the document later. The usermay alternatively fill in the fields by dragging the document over atool which has been set up to automatically fill in certain fields ofthe information sticker. Once the desired fields are added and filledin, there is no need to "file" the document in the traditional sense.The user can remove it from the workspace, put it in a pile, or retrieveit later using the values typed in the information sticker fields. As analternative to stapling information stickers to new documents, thesystem may use another means of annotation, such as making the newdocument a specific color, or writing text to an attribute or editablefield of the new document.

To add a note to a document, for example when the document is shared bymultiple users, a user can also staple a sticker onto a document. Thesticker is actually a simple text document that can be edited by theuser.

Any page of any document can have a sticker stapled to it. To get asticker, the user shift-drags a sticker off of a sticker pad.Specifically, the user may move the mouse cursor over a sticker padscreen object, press the mouse button and the shift key simultaneously,and remove a sticker off of the sticker pad. The user then moves thesticker over a document and releases the mouse button and shift key tostaple the sticker to the document.

Clip Marks on Stickers

To add more information than there is room to add on the sticker, theuser may pull down on the clip mark to make more room in which to type.To make the sticker small again, the user may grab the clip mark anddrag it up until the sticker is the desired size.

Removing a Document from the Workspace

Removing a document from the workspace may cause the document, and itspermanent attributes to be written back to the repository. When adocument is removed from the workspace, the ephemeral attributes forthat document within that workspace are lost. To remove a document fromthe workspace in an example embodiment, the user holds down the Shiftkey and drags the document out of the workspace window. When the mousebutton is released while the document is outside of the window, thedocument or documents being dragged will be removed from the workspace.The documents are not deleted from their repositories, just from theworkspace.

Sharing Documents Among Multiple Users

A first user and a second user sharing a repository can share documents.For example, a first user may show a document to a second user using aSHOW TO tool. The system allows the first user to call the document tothe attention of the second user, and add a note to it if needed. Thefirst user first selects the document and locates the SHOW TO tool inthe tool rack. The first user then presses the SHOW TO tool's button byclicking the mouse over the button displayed on the SHOW TO tool, andthe SHOW TO tool unclips one clip stop. Next, the first user enters theusername of the second user, and optionally, a note regarding theselected document. The first user then presses the SHOW TO tool's buttona second time, and the SHOW TO tool clips to its original size, and thedocuments remain where they are in the current workspace.

The person named will find the document in his or her IN BOX pile. Aninformation sticker is added to the top of any document called tosomeone's attention. The sticker has the first user's name and the dateit was called to their attention, along with any notes typed by thefirst user. If the document already has an information sticker on it, anew one with the new information is placed on top of it.

If the first user enters more than one name into the SHOW TO tool, thedocument is called to the attention of each of those users.

To create a customized SHOW TO tool to bring documents to the attentionof a second user, the first user first selects the SHOW TO tool. Thefirst user then presses the button on the DUPLICATE tool in the toolrack, or drops the SHOW TO tool onto the DUPLICATE tool. A new tool isthus created called "SHOW TO copy". The first user then changes thetitle of the tool so it contains the second user's name. Every time thistool is used, either by selecting documents and clicking its button, orby dropping documents on it, it marks the documents to the attention ofthe second user.

As stated above, when the first user calls a document to the seconduser's attention, the document appears piled under the IN BOX of thesecond user. When several new documents are called to the second user'sattention at once, the first one to arrive is on top of the pile, thenext to arrive just behind that, and so on. Documents on the pile thathave already been seen but that have been left on the IN BOX pile arepiled behind the batch of new documents.

When a document is piled in an IN BOX pile because a first user hasmarked it for a second user's attention, an information sticker isplaced across the top of the document. A document that has not been readhas a colored line across the top of the new document's informationsticker. Other documents in the IN BOX pile have no colored line ontheir information sticker.

To read a document from the IN BOX, the user grabs it by the corner andpulls it close to the front of the workspace. Then the informationsticker can be moved in order to see all of the first page of thedocument. The sticker can be moved to some other place on the documentor pulled completely off.

The sticker may have a hidden message. To read the hidden message, thesticker must be unclipped. When the sticker is moved or unclipped, itscolored line will disappear, signifying that the document is no longernew.

Every time a document is called to a user's attention, it is piled nearthe IN BOX if that tool is in the user's workspace. The user can set thetime when documents are gathered, either to collect them only whenrequested or constantly.

Using Ephemeral Attributes to Share Documents Among Multiple Users

FIG. 15 shows an apparatus for sharing the visual display of a documentusing ephemeral attributes. A first user 120a and a second user 120b areshown sharing a document 405. The first user 120a is shown using displaydevice 160a. The display device 160a is shown coupled with a workspaceviewer process 128a and a document renderer process 136a. The workspaceviewer process 128a and document renderer process 136a are coupled withworkspace cache 132a. The workspace cache 132a contains a first copy405a of document 405, as well as ephemeral attributes 406a describingthe visual display of document 405 on the display device 160a. Theworkspace cache 132a is coupled with a client module 210a and a networkconnection 400. The client module 210a is coupled with a LAN 211. Thenetwork connection 400 may optionally be coupled with the LAN 211.

A second user 120b is shown using a second display device 160b. Thesecond display device 160b is shown coupled with a second workspaceviewer process 128b and a second document renderer process 136b. Thesecond workspace viewer process 128b and second document rendererprocess 136b are coupled with second workspace cache 132b. The secondworkspace cache 132b contains a second copy 405b of document 405, aswell as ephemeral attributes 406b describing the visual display ofdocument 405 on the second display device 160b. The second workspacecache 132b is coupled with a second client module 210b and the networkconnection 400. The second client module 210b is coupled with the LAN211. The network connection 400 may optionally be coupled with the LAN211.

During operation of the elements in FIG. 15, the first user 120areferences document 405, and the client module 210a requests thatdocument 405 be retrieved from the repositories 142 over LAN 211. Theclient module 210a receives document 405 over LAN 211, and the firstcopy 405a of document 405 is written into workspace cache 132A. As thefirst user 120a manipulates the display of document 405 on displaydevice 160a, the values of ephemeral attributes 406a change to reflectthe actual display of document 405 on display device 160a.

Further during operation of the elements in FIG. 15, the second user120b requests the document 405 be retrieved from the repositories 142over LAN 211. The second client module 210b requests that document 405be retrieved from repositories 142 over LAN 211. The second client 210breceives document 405 over LAN 211, and the second copy 405b of document405 is written into the second workspace cache 132b. The ephemeralattributes 406a are then transmitted through the network connection 400,and written into second ephemeral attributes 406b. The second ephemeralattributes 406b are then used by the second workspace viewer 128b, andthe second document renderer 136b to display document 405 on seconddisplay device 160b, such that second user 120b views document 405consistent with the display of document 405 on display device 160a, asseen and manipulated by the first user 120a.

As an alternative method for sharing the visual display between the twousers, the ephemeral attributes 406a and 406b could be promoted topermanent attributes by each user, and then stored back to therepositories 142. Each client module may then access the repositories142 to retrieve those permanent attributes, convert the permanentattributes to ephemeral attributes, and update the local display.

Creating a Document via the Merging of Existing Documents

FIG. 16 is a diagram of a method for merging multiple documents based ontheir visual display attributes. A first document 500 is shownassociated with ephemeral attributes 502 within a first workspace 506.Applying ephemeral attributes 502 to first document 500 result in thefirst workspace 506 having screen object 504 representing first document500. Similarly, second ephemeral attributes 512 applied to a seconddocument 510 result in a second workspace 516 having a screen object 514representing second document 510.

A merging process 520, typically implemented in script language, takesas input first document 500, ephemeral attributes 502, second document510, and ephemeral attributes 512. The merging process 520 outputs a newworkspace document 522, including a copies of the first document 500a,ephemeral attributes 502a, second document 510a and ephemeral attributes512a. The new workspace document 522 produces a visual display 540having screen objects 542 (corresponding to screen object 504), and 544(corresponding to screen object 514).

A Multithreaded System for Retrieving Documents

FIG. 17 shows a multithreaded system for retrieving documents, includinga display device 1750 coupled to a client device 1700. The client device1700 includes a multithreading environment 1730, the multithreadedenvironment having a icon display means 1705, a cursor display means1710, a launching means 1715, a desired process 1720, a retrieving means1725, and a means for returning 1727. The client device 1700 is furthercoupled with a user interface device 1760, and repositories 1765.

During operation of the elements shown in FIG. 17, the client devicedisplays an icon 1755, through the icon display means 1705, and acursor, through the cursor display means 1710, on the display device1750. The user manipulates the user interface device 1760 to issue asignalling command to the client device 1700, the signalling commandrequesting that desired process 1720 be executed. The client device 1700receives the signalling command, and the launching means 1715 thenlaunches the desired process 1720, such that the desired process 1720runs within the multithreaded environment 1730. The desired process 1720then executes on the CPU 1740. Before the desired process 1720 completesexecution, the cursor display means 1710 is allowed to execute on theCPU 1740, thereby maintaining an active cursor while the desired process1720 makes progress in execution.

It is to be understood that the invention is not necessarily limited tothe particular embodiment shown herein. The invention may be adapted toa wide variety of information management systems. It is also to beunderstood that various adaptations and modifications may be made withinthe spirit and scope of the invention.

What is claimed is:
 1. An apparatus for displaying documents,comprising:a computer controlled display device; means for displaying astrand of documents on said display device, said strand having a parentdocument and one or more child documents, said parent documentrepresented on said display device by a screen object, each one of saidchild documents represented on said display device by a screen objectdisplayed on a strand path, said strand path consisting of a twodimensional line through a three dimensional virtual display space inwhich said parent document and said child documents are arranged; saidparent document including a strand function, said strand function beingan attribute having a value equal to a script representation of amathematical equation which when interpreted and executed outputs thecoordinates of said strand path; and each one of said child documentsidentified by an entry in a child document list contained within saidparent document, each entry in said child document list containing aunique identifier for one of said child documents.
 2. The apparatus asin claim 1, further comprising:a workspace viewer process formaintaining said three-dimensional virtual display space, said threedimensional virtual display space known as a workspace; a perspectivefunction, within said workspace viewer process, for translatingcoordinates of said parent document and said child documents in saidthree-dimensional workspace from three-dimensional coordinates into twodimensional screen coordinates.
 3. The apparatus as in claim 2, furthercomprising:a processor; a memory coupled with said processor; saiddocuments stored as data in said memory; said perspective functionconsisting of software stored in said memory and executing on saidprocessor.
 4. The apparatus as in claim 1, further comprising:userinterface means for manipulating the position of said strand asdisplayed on said display device.
 5. The apparatus as in claim 4, saiduser interface means further comprising:a mouse; and strand movingmeans, responsive to said mouse, for selecting said strand and movingthe location of said strand as a whole in said workspace.
 6. Theapparatus as in claim 5, further comprising document removing means,responsive to said mouse, for selecting one of said child documents, andremoving said child document from said strand by dragging said childdocument off of said strand path.
 7. The apparatus as in claim 1,saidparent document including a minimum spacing constraint defining aminimum distance along said strand path between each screen object onsaid strand.
 8. The apparatus as in claim 1, said parent documentincluding a maximum spacing constraint defining a maximum distance alongsaid strand path between each screen object on said strand.
 9. Theapparatus as in claim 1, said parent document including a knotconstraint, defining a point on said strand path, such that any of saidchild documents displayed between said parent document and said knotconstraint belong to a first sub-strand, and all other of said childdocuments belong to a second sub-strand.
 10. The apparatus as in claim1, said parent document including an origin constraint, said originconstraint defining the position of said strand on said display devicerelative to the screen object of said parent document.
 11. The apparatusas in claim 1, wherein said display device is a CRT.
 12. An apparatusfor displaying documents, comprising:a processor; display memory meanscoupled with said processor; a display device, coupled with said displaymemory means, for displaying screen objects described in screencoordinates stored in said display memory means; document memory means,coupled with said processor, for holding one or more documents; one ormore child documents stored in said document memory means; a parentdocument stored in said document memory means, said parent documenthaving a strand function, said strand function being an attribute havinga value equal to a script representation of a mathematical equationwhich when interpreted and executed outputs the coordinates of a strandpath; one or more screen objects representing each one of said one ormore child documents and displayed on said display device on said strandpath; script interpreter means, coupled with said document memory means,for interpreting and executing said strand function and outputting threedimensional world space coordinates of said strand path; and perspectivefunction means, coupled with said processor, said display memory means,and said document memory means, and responsive to said three dimensionalworld space coordinates, for translating said world space coordinatesinto two dimensional screen space coordinates, and storing said screenspace coordinates into said display memory means.
 13. The apparatus asin claim 12, further comprising:said script interpreter means and saidperspective means are computer programs executing on said processor; andsaid strand function is code stored as a high level language in saidparent document, and said strand function is interpreted into executablecode by said script interpreter means, and said executable code isexecuted on said processor.
 14. The apparatus as in claim 12 said parentdocument further comprising:a child document list identifying all childdocuments on said strand; a strand minimum constraint defining a minimumdistance between screen objects on the strand; a strand maximumconstraint defining a maximum distance between screen objects on thestrand; and a strand origin constraint defining a position of saidstrand relative to position of a screen object representing said parentdocument on said display device.
 15. The apparatus as in claim 12 eachone of said one or more child documents further comprising:a strandposition constraint defining a location of a screen object representingsaid child document on said strand on said display device relative tosaid parent document; and a strand parent constraint identifying saidparent document.
 16. The apparatus as in claim 12 further comprising:auser interface, having a user interface device, for dragging screenobjects shown on said display device; said parent document including achild document list, each element in said child document list containinga unique identifier of one of said one or more child documents; documentinserting means, responsive to a screen object of a new document beingdragged into contact with said strand path, for inserting said documentinto said strand by adding a unique identifier for said new document tosaid child document list in said parent document, said new documentthereby becoming a child document of said strand.
 17. The apparatus asin claim 16, further comprising:document removing means, responsive to ascreen object corresponding to one of said on or more child documentsbeing dragged off of said strand path, for removing a unique identifierof said on of said one or more child documents from said child documentlist in said parent document.
 18. The apparatus as in claim 16, whereinsaid user interface device is a mouse.
 19. The apparatus as in claim 16,wherein said user interface device is a track ball.
 20. The apparatus asin claim 16, wherein said user interface device is a touch sensitivedisplay screen.
 21. The apparatus as in claim 16, wherein said userinterface device is a light pen.
 22. The apparatus as in claim 16,wherein said user interface device is a pressure sensitive pad forinputting user handwriting.